Data Equalisation in a Communication Receiver with Transmit and Receive Diversity

1. A method for performing data equalisation in a communication receiver, the communication receiver forming part of a communication system with transmit and receive diversity, the method including the steps of: (a) for each i-th receiver antenna and j-th transmitter antenna, calculating a channel response matrix H i,j from multi-path channel estimates; (b) each i-th receiver antenna, calculating a channel gain matrix G i from the channel response matrices H i,j and a scalar noise factor β; (c) calculating the middle column c 0 of the inverse G i −1 of the channel gain matrix G i ; (d) calculating filter coefficient vectors w i,j from the middle column c 0 of the inverse G i −1 of the channel gain matrix G i and the Hermitian transpose H i,j H of the corresponding channel response matrices H i,j ; (e) filtering input data r i received at each i-th receiver antenna with the corresponding filter coefficient vectors w i,j ; (f) despreading the filtered input data from each i-th receiver antenna; (g) applying phase compensation to the despread data; and (h) combining the despread data from all antennas to obtain received equalised data.

2. A method according to claim 1 , wherein step (c) includes: (h) performing a Cholesky decomposition of each channel gain matrix G i into a lower triangular matrix L and an upper triangular matrix U; (i) performing forward substitution on the lower triangular matrix L to calculate a column vector d; and (j) performing backward substitution on the column, vector d and the Hermitian transpose L H of the lower triangular matrix L to calculate the middle column c 0 of the inverse G i −1 of the channel gain matrix G i .

3. A method according to claim 1 , wherein the channel gain matrix G i to be inverted is calculated from the expression G i = ∑ 1 j ⁢ H ^ i , j H ⁢ H ^ i , j + β ~ i ⁢ I where I is the identity matrix.

4. A chip equaliser for use in a communication receiver forming part of a communication system with transmit and receive diversity, the chip equaliser including one or more computational blocks for carrying out a method according to claim 1 .

5. A method according to claim 2 , wherein the channel gain matrix G i to be inverted is calculated from the expression G i = ∑ 1 j ⁢ H ^ i , j H ⁢ H ^ i , j + β ~ i ⁢ I where I is the identity matrix.

6. A chip equaliser for use in a communication receiver forming part of a communication system with transmit and receive diversity, the chip equaliser including one or more computational blocks for carrying out a method according to claim 2 .

7. A chip equaliser for use in a communication receiver forming part of a communication system with transmit and receive diversity, the chip equaliser including one or more computational blocks for carrying out a method according to claim 3 .

8. A chip equaliser for use in a communication receiver forming part of a communication system with transmit and receive diversity, the chip equaliser including one or more computational blocks for carrying out a method according to claim 5 .